The present invention relates to a semiconductor integrated circuit device, and more particularly to a technique that can be effectively applied to, for instance, a system large scale integrated circuit (LSI) in which each of a plurality of functional modules is divided into circuit blocks and power supplied is turned on or off according to the operation or non-operation of each functional module.
There is Japanese Unexamined Patent Publication No. 2002-026711, which discloses a configuration in which the circuit is divided into a circuit block consisting of a MOSFET having a low threshold voltage and a circuit block consisting of a MOSFET having a high threshold voltage, the leak current is reduced by cutting off power supply to the circuit blocks of the low threshold voltage in the standby mode when the semiconductor integrated circuit device is not operating, and a gate circuit known as a wrapper is provided on the route on which its input signals and output signals are communicated. Also, the existence of Japanese Unexamined Patent Publication No. 2003-218682 is reported, which discloses a configuration comprising a sending-side circuit block having a power switch, a receiving-side circuit block, and a micro I/O circuit for supplying output signals from the sending-side circuit block to the receiving-side circuit block as input signals, in which the micro I/O circuit prevents the output signals from being propagated with a control signal from the receiving-side circuit block when power supply to the sending-side circuit block is cut off by the power switch. However neither of these patent references makes any mention of technical problems the invention under this application intends to solve.
[Patent Reference 1] Japanese Unexamined Patent Publication No. 2002-026711
[Patent Reference 2] Japanese Unexamined Patent Publication No. 2003-218682